Pulse magnitude regulating system



July 4, 1967 D. K. GRIMM ET AL PULSE MAGNITUDE REGULATING SYSTEM 2 $heets-$heet 2 Filed April 8 1963 3 $18 @9365 X522 w o IIIIIIIL Flll INVENTORS DONALD K. GR/MM ADRIAN E. GLANDON ATTORNEYS United States Patent C M 3,329,829 PULSE MAGNITUDE REGULATING SYSTEM Donald K. Grimm, Fargo, N. Dak., and Adrian E. Glandon, Cedar Rapids, Iowa, assignors to Collins Radio Company, Cedar Rapids, Iowa, a corporation of Iowa Filed Apr. 8, 1963, Ser. No. 271,196 3 Claims. (Cl. 307-88) ABSTRACT OF THE DISCLOSURE 7 Memory devices requiring the use of multiaperture magnetic cores require a pulse source for supplying drive pulses to the core and also a pulse source for supplying prime pulses to the core. The cores also are supplied with blocking pulses by a third pulse source.,Because three pulses are used at least two must be of the same polarity. Consequently, the drive winding and blocking winding are usually wound with the same polarity. It is therefore necessary to maintain the level of the drive pulses between maximum and minimum levels. A maximum level is required to prevent spurious unblocking of the core by a pulse of excessive amplitude. A minimum level is required to insure switching of the core flux upon application of a drive pulse. This invention therefore describes a system for maintaining the amplitude of the driving pulses between a selected set of maximum and minimum values.

This invention relates to a pulse magnitude regulating system and more particularly to a system for regulating the magnitude of interrogation pulses coupled to multiaperture magnetic memory cores.

A multiaperture magnetic memory core device, or transfluxor, includes a ferrite core having rectangular hysteresis characteristics and the ability to store a level of control established by a set current. The operation of the core is dependent upon the transfer of flux from one leg to another in the magnetic circuit.

The transfluxor is known in the art and is explained, for example, in an article entitled The Transfluxor by J. A. Rajchman and A. W. Lo appearing in the Proceeding of the IRE, volume 44, number 3, pages 321- 332, March 1956. I

A multiaperture core is commonly first blocked, or cleared,'by passing a large blocking current through a blocking winding (wound about the major aperture of the core). Once cleared, the core may then be set by passing a set current through the set winding (wound about either the major or minor aperture of the core), the direction of this current being opposite to that of the blocking current coupled through the major aperture.

Interrogation of the core is accomplished by alternate drive and prime pulses (the A-C drive and prime has been described herein as pulses since pulses have been found to be preferable to other types of A-C energization, such as a sinusoidal signal, for example). The drive pulse is coupled to the drive winding of the core (wound about the minor aperture) so that the drive current is opposite to that of the set current and will produce an output from the core (the output winding also being wound about the minor aperture) if the core is in a set condition, but not if in a blocked condition. The prime pulse is coupled to the prime winding of the core (wound about the minor 3,329,829 Patented July 4, 1967 aperture) so that the prime current is opposite to that of the drive current.

When interrogating magnetic memory cores, the drive pulses must be of sufficient amplitude to insure switching of all flux about the minor aperture of the core and simultaneously deliver an adequate amount of energy to the load, while the prime pulses must be of a magnitude to insure at least partial switching of the flux about the minor aperture but none about the major aperture. Thus, unlike drive pulses, prime pulses have both an upper and a lower magnitude limit. This is due to the direction of the prime current, which, unlike the drive current, is in a direction that can cause spurious unblocking of the core (by reversing the flux about the major aperture) if the magnitude is not controlled.

By maintaining the interrogation pulses above a predetermined minimum value, driving and priming of the storage cores is assured even though operating conditions may change, as can occur, for example, due to variations in power supply or ambient temperatures. By maintaining the prime pulse below a predetermined maximum value, spurious unblocking of the storage cores is precluded.

It is an object of this invention to provide a regulating system capable of automatically regulating the magnitude of the interrogation signal coupled to magnetic. memory cores.

It is another object of this invention to provide a pulse magnitude regulating system capable of regulating the magnitude of pulses coupled to a magnetic memory core to preclude spurious unblocking of the core.

It is yet another object of this invention to provide a pulse magnitude regulating system having sampling means for sampling the output of an interrogation pulse generator used to interrogate magnetic memory cores, means for converting the sampled voltage to a direct current signal and then coupling the voltage back to the interrogation generator to control the magnitude of the pulses produced and thereby assure proper core operation.

It is still another object of this invention to provide a pulse magnitude regulating system having means for sampling the output of a drive pulse generator, means for converting the sampled output signal to a direct current signal and means for coupling the direct current signal to the input of a prime pulse generator whereby the prime pulses coupled to magnetic memory cores are prevented from causing spurious unblocking of the cores.

With these and other objects in view which will become apparent to one skilled in the art as the description proceeds, this invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiments of the herein disclosed invention may be included as come withinthe scope of the claims. i

The accompanying drawings illustrate two complete examples of the embodiments of the invention constructed according to the best mode so far'devised for the practical application of the principles thereof, and in which:

FIGURE 1 is a partial schematic presentation of one embodiment of the pulse magnitude regulating system of this invention for assuring suflicient drive for proper core nitude regulating system of this invention wherein the detected output signal is utilized to regulate the amplitude of the prime pulses to assure optimum prime current for proper core operation thereby preventing spurious unblocking of magnetic memory cores.

Referring now to the accompanying drawings in WhlCh like numerals refer to like characters throughout, the numeral 5 indicates generally the pulse magnitude regulating system of this invention. The system includes a sampling core 6, a sampling detector 7, and a low pass filter 8.

As shown in the drawings, the pulse output from drive pulse generator 10, controlled by a conventional clock pulse generator 11, is coupled to a core matrix 12 to drive the storage cores 14 (as shown in FIGURE 2) therein. Core matrix 12 is connected to a plurality of sense detectors 15, each of which detectors provides a D-C output for readout purposes.

Storage cores 14 in core matrix 12 are shown in FIG- URE 2 to consist of a plurality of multiaperture cores. The windings on the cores are conventional, and include set, prime, drive, and output windings (16, 17, 18, and 19, respectively) wound about the minor aperture, and a blocking winding wound about the major aperture. As is also conventional, each winding is driven by a pulse generator, with blocking pulse generator 21 being connected to blocking winding 20, set pulse generator 22 being connected to set winding 16, and prime pulse generator 23 being connected to prime winding 17. All generators may be externally controlled by a programmer in conventional fashion, for example, by a clock pulse generator.

Sense detectors 15 may be identical to the detector shown in detail in FIGURE 2. As shown, this detector in cludes a first transistor 24 having its base and emitter connected to the output winding 19 of one storage core 14, and a capacitor 25 connected in shunt with transistor 24. In addition, a second transistor 26 has its base connected to one side of capacitor 25 and to the emitter of transistor 24, its collector connected to the other side of capacitor 25 and to the collector of transistor 24, and its emitter grounded. A DC voltage is developed across load resistor 28, one side of which is connected to a +28 volt D-C source (not shown) and the other side of which is connected to the collector of transistor 26. The detected voltage is coupled from the detector through output leads 29 and 30 for readout purposes.

As shown in both FIGURES 1 and 2, the output from drive pulse generator 10 is also coupled through lead 31 to drive winding 32 (wound about the minor aperture of sampling core 6), the other end of said winding being connected to a +28 volt D-C power supply (not shown). Sampling core 6 is a multiaperture core device and may be identical in structure to storage cores 14. As shown, sampling core 6 has a blocking winding 33 wound about the major aperture, and set, prime, and output windings (34, 35, and 36, respectively) wound about the minor aperture. As is conventional, each is connected to a pulse generator which generator, like the pulse generators connected to the storage cores, may be externally controlled, as by a clock pulse generator. As shown in the drawings, blocking pulse generator 37 is connected to blocking winding 33, set pulse generator 38 is connected to set winding 34, and prime pulse generator 23 is connected to prime winding 35. Unlike the storage cores, each of which may or may not be in a set state, the sampling core is always left in a set state. The output winding 36 of sampling core 6 has one end connected to ground and the other end connected to detector 7.

Detector 7 is similar in structure to sense detectors 15 and includes a transistor 40 the base of which is connected to output winding 36. A capacitor 41 is connected in shunt across transistor 40, being connected between the emitter and collector of the transistor. In addition, a second transistor 42 has a grounded emitter, its base connected to one side of capacitor 41 and the emitter of transistor 40, and

its collector connected to the other side of capacitor 41 and to the collector of transistor 40. Detector 7 detects the incoming signal and produces a D-C voltage that is proportional to the input signal. Because of the added voltage drop in series with the detector input provided by returning output winding 36 to ground, sampling detector 7 provides more attenuation than do sense detectors 15. Sense detectors 15 and sampling detector 7 form the subject matter of copending United States Patent No. 3,188,- 495, filed Apr. 8, 1963 by Donald K. Grimm and assigned to the assignee of the present invention.

The output from detector 7 is coupled to low-pass filter 8 consisting of a resistor 44 and a capacitor 45, the latter being connected between ground and one side of the resistor.

As shown in FIGURE 1, the output from low-pass filter 8 is coupled to drive pulse generator 10, and, as shown in FIGURE 2, the output from filter 8 is coupled to prime pulse generator 23. The drive and prime pulse generators may be identical and each includes a transistor 46 from which the pulse output is taken from the collector. Conduction of transistor 46 is controlled from an external source, shown in the drawings to be clock pulse generator 11. The pulse from the external source (preferably +28 volts) is coupled to the base of transistor 46 through resistor 47. The emitter of transistor 46 is returned to ground through resistor 48, and the D-C voltage from detector 7 (through low-pass filter 8) is coupled to the base of transistor 46 through diode 49 to control the amplitude of the pulse produced by the generator.

In operation of the FIGURE 1 embodiment, the drive pulses are sampled and the magnitude of these pulses controlled by the feedback network (sampling core 6, detector 7 and filter 8). The purpose of this is to assure that the drive pulse will have at least a minimum amplitude necessary to drive all cores in the core matrix. This result is assured since the sampling detector, by its construction, will be rendered conductive after the sense detectors (because of the extra voltage drop in series with the detector input-the output winding on core 6 being returned to ground while the output winding on cores 14 are connected to the emitter of transistor 26 of detector 15). The embodiment of FIGURE 1 therefore assures sufiicient drive for proper core operation even though variances occur, such as in power supply voltages or in ambient temperatures.

In the embodiment of FIGURE 2, the output pulses from drive pulse generator 10 are sampled while the output from low-pass filter 8 is used to control the magnitude of pulses produced by prime pulse generator 23. The prime pulses must not only be controlled as to minimum value but must also be controlled as to maximum value. This is in contrast to the drive pulses which have no maximum limitation since they are in a direction which cannot upset the flux around the major aperture of the multiaperture core.

The minimum limit of the prime pulse is dependent upon the level of the drive pulse in that sufficient flux must be reversed by the pirme pulse to enable the drive pulse to transfer the required energy to the load (appreciable energy may be transmitted to a load from a drive pulse during the time the core is switching since there is no danger of spurious unblocking, and for this reason the core output which occurs during the drive pulse is used to provide the input to the sense detectors). The maximum limit of the prime pulses is that value just below the value which will cause flux reversal around the major aperture and cause spurious unblocking of the core.

In operation, the invention as shown in the embodiment of FIGURE 2, will always maintain the prime pulses at a level that will reverse only part of the available flux, providing that an excess of flux is available in the cores being interrogated. This assures that the prime pulses can never approach a level which will cause spurious unblocking of the multiaperture cores.

The following components may be utilized in constructing a working embodiment of this invention. It is to be realized, however, that this invention is not meant to be limited to the particular component values, which are as follows In view of the foregoing, it should be evident to those skilled in the art that the regulating system of this invention provides a novel means for regulating the interrogation pulses coupled to multiaperture cores.

What is claimed as our invention is:

1. A pulse magnitude regulating device, comprising: pulse generating means the output pulses of which are coupled to magnetic memory core devices for interrogation purposes; a multiaperture magnetic memory core device having a major aperture and a minor aperture, said core device having wound thereon through said minor aperture an input winding connected to receive said output pulses, said core device having an output winding; voltage level controlling detecting and attenuating means comprising a voltage level controlling circuit, connected to said output Winding; means for supplying blocking pulses to a winding through said major aperture; and means including a low pass filter for coupling the direct current output signal from said detecting and attenuating means to said pulse generating means to thereby assure that the magnitude of said output pulses will be sufiicient for interrogation of said magnetic memory core devices.

2. A pulse magnitude regulating device, comprising: drive pulse generating means the output pulses of which are coupled to multiaperture memory core devices to switch the flux about the minor aperture in a predetermined direction that cannot cause spurious unblocking of the core; prime pulse generating means the output pulses of which are coupled to said multiaperture memory core devices to switch the flux about the minor aperture in the direction opposite to said predetermined direction; sampling means connected to receive the output pulses from said drive pulse generating means; means connected to said sampling means for receiving the output therefrom and in response thereto developing a direct current output signal the magnitude of which is dependent upon the magnitude of the pulses from said drive pulse generating means; and means for coupling the direct current output signal from said last named means to said prime pulse generating means to control the magnitude of the output pulses therefrom whereby spurious unblocking of the multiaperture cores is prevented.

3. A pulse magnitude regulating device, comprising: drive pulse generating means the output pulses of which are coupled to multiaperture memory core devices to produce clockwise flow in the magnetic material of said devices; prime pulse generating means the output pulses of which are coupled to said multiaperture memory core devices to produce counterclockwise flow in the magnetic material of said devices;' a sampling multiaperture memory core device having at least a pair of windings Wound about said minor aperture one of which is connected to receive the output pulses from said drive pulse generating means; detecting and attenuation means connected to the other Winding of said sampling multiaperture memory core device to develop a direct current output signal having a magnitude dependent upon the magnitude of said output pulses from said drive pulse generating means; and means for coupling said direct current output signal to said prime pulse generating means to control the magnitude of the pulses produced therefrom whereby said pulses will be maintained at a level to reverse only a portion of the available flux of the cores of said multiaperture core devices to assure against spurious unblocking of said cores by said pulses from said prime pulse generating means.

References Cited UNITED STATES PATENTS 2,919,434 12/ 1959 Mestre 307-88 3,073,967 l/l963 Phillips 30788 3,239,681 3/1966 Bond 307-88 BERNARD KONICK, Primary Examiner.

M. S. GITTES, Assistant Examiner. 

1. A PULSE MAGNITUDE REGULATING DEVICE, COMPRISING: PULSE GENERATING MEANS THE OUTPUT PULES OF WHICH ARE COUPLED TO MAGNETIC MEMORY CORE DEVICES FOR INTERROGATION PURPOSES; A MULTIAPERTURE MAGNETIC MEMORY CORE DEVICE HAVING A MAJOR APERTURE AND A MINOR APERTURE, SAID CORE DEVICE HAVING WOUND THEREON THROUGH SAID MINOR APERTURE AN INPUT WINDING CONNECTED TO RECEIVE SAID OUTPUT PULSES, SAID CORE DEVICE HAVING AN OUTPUT WINDING; VOLTAGE LEVEL CONTROLLING DETECTING AND ATTENUATING MEANS COMPRISING A VOLTAGE LEVEL CONTROLLING CIRCUIT, CONNECTED TO SAID OUTPUT WINDING; MEANS FOR SUPPLYING BLOCKING PULSES TO A WINDING THROUGH SAID MAJOR APERTURE; AND MEANS INCLUDING A LOW PASS FILTER FOR COUPLING THE DIRECT CURRENT OUTPUT SIGNAL FROM SAID DETECTING AND ATTENUATING MEANS TO SAID PULSE GENERATING MEANS TO 